Rifle-bullet.



No. 807,012. PATENTE-DB0. 12, 1905.

LLBBLL. f RIFLE BULLET.

APPLICATION FILED JUNE 26. 1905.

I let through the barrel.

'narran erariale PATENT FFIQE RiFLE-BULLEF.

no. sof/,012.

Specification of Letters Patent.

Patented Dec. 12. 1905.

Application filed Juno 26. 1905l Serial No. $66,980.

T0 all whom, it may concern,-

Be it known that l, JAMES E. BELL, a citizen of the TJnited States, residing at ill/'ashington, in the District of Columbia, have invented certain new and useful improvements in Ride-Bullets, of which the following is a specification.

lhe'service-buhets employed in the United States and other military rilles having a caliber of about thirty-hundredths of an inch have a length which is several times their diameter. To maintain the axes of these long bullets in the line of flight, it is necessary to give them a rapid axial rotation. To effect this rotation, the bore of the United States rifle has four helical grooves with a pitch of ten inches, the width of each groove being 0.1767 inch and its depth 0.004 inch, the width of the intermediate lands being 0.0589 inch. On account of this rapid twist a softlead bullet cannot be used in military rilles, as when driven through the barrel with high velocity by a charge of smokeless powder the bullet will not fo ow the grooves, and the lands will shear olf the portions of the lead lt is therefore usual to employ a composite bullet having a soft core of lead and a thin jacket of harder metal, such as a nickel-copper alloy, the core giving the necessary weight, while the jacket holds the indentations produced by the lands. The jacketed bullets give satisfactory results so far. as accuracy is concerned, but have serious defects. A considerable portion of' the energy of the powder charge-said to be forty per cent.-is required to drive the bul- This consumption of energy is largely due to the fact that theoullet when expelled from the cartridge must instantly conform itself to the shape of thc rilied bore, the lands pressing spiral recesses into the cylindrical portion of the bullet, which usually about live-eighths its total length. Time is required to ell'ect this change in the shape oi the bullet, and its movement through the barrel is thereby retarded. 'lhe friction between the barrel and the long cylindrical body of tho bullet also retards the bullet, so that the pressure ol' the powder-gases rises to la high ligure, wnile the metal of the barrel is worn away by the hardmetal jacket to such an extent that it soon gives inaccurate results.

rl`he present bullet also consists of a softrnetal core and a acket of harder metal; but

`sists ofthe core l and the j ackct 2.

the body of the bullet is not of uniform diameter. The bullet comprises a point of the usual form, a relatively long cylindrical body having a diameter substantially equal to the bore of the rifle in which it is to be used, and a relatively short cylindrical base portion having a diameter substantially equal to that of a circle coincident with the base of the grooves of the rifle.

Referring to the accompanying drawings, Figure l is a side elevation of the improved bullet. Fig. 2 is a side elevation of the bullet-core, showing the jacket in vertical seotion. Fig. 3 is a side elevation of a rifle-barrel, showing the bullet in elevation therein. Fig. 4 is a transverse section on the line .4,4 of Fig. 3, and Fig. 5 is a transverse section .on the line 5 5 of Fig. 3.

The bullet chosen forillustration is designed for the United States Army rifle, and con--` The bullet comprises a point 3, a long body portion 4, and a base portion 5, there being a tapering shoulder 6 between the portions 4 5. The diameter of the body portion l is substantially equal to the bore of the United States riIle-that is, 0.300 inch. It is therefore Aadapted to bear smoothly and with little friction upon the lands 9 of the rifle 7 as shown in Figs. 3 and 5. The base portion 5 is intended to take the rilling and rotate the bullet and to serve as a gas-check, Its diameter is substantially equal to that of the circle coincident with the base of the grooves of the riflethat is, about 0.308 inch. It has been found by experiment that the length of the base portion need not exceed one-half the diameter of the bullet--that is, 0. 15 inch. This length is suilicicnt to rotate the bullet without strippingl and to prevent the escape of tho powdergases. The rifle-lands 0 press short helical iudcntations 10 into the base portion, While the base iills the grooves, as shown in Figs 3 and 4.

Careful tests of the improved bullet in the United States Krag Jorgensen rifle have shown that under otherwise identical conditions wil h a charge of 533.4- grains of Lallin and tand W'. A. smokeless powder this bullet rcducos tho average pressure of the powdergases in the barrel from thirty-two thousand four hundred and twcnty pounds por square inch with the standard bullet to twentysevcn thousand nine hundred and sixty pounds without substantially allecting the` C )incident d, um @l my Signature A mi Ji bunch fm BELL. Iier-50110 m? if BUN 

